Supporters of the banned group Lashkar-e-Taiba at a rally in Kashmir.
Photograph: Alamy Stock Photo

Two years ago, while researching a book on migration, I visited West Java. One day, while driving through the uplands of Subang, I saw, among the acres of tea and coffee plantations, a huge white edifice. At first I thought it was a mosque: it had a big dome and minarets. But as we drew nearer, I realised it was a cluster of several buildings. When I quizzed my driver, he said that it was indeed a mosque and the buildings attached to it comprised a boarding school. Before I could ask what such an obviously expensive complex was doing in a rural backwater, he added that it was a Saudi-funded establishment. It was one of many, he said, that had cropped up all over West Java in recent years. Did he know anyone who attended that school? He was not local to the area but, he said, near his own village, a similar Saudi-funded school had appeared a while back. Impressed by its spacious grounds and imposing building, he had moved his 10-year-old son there, but within a few weeks he had hastily returned him to his ramshackle old village school. His son had begun, he reported, to express some alarming ideas about “true Islam” and berate his Muslim parents for their easygoing ways.

“You mean it was a madrasa?” I asked him.

“You know the word?”

Yes, I know the word. Originally meaning a seminary for learning the Qur’an and subjects such as philosophy and mathematics, the word “madrasa” has assumed darker connotations in my country of birth, Pakistan. To be fair, a small minority are still that – ordinary schools – but most of Pakistan’s 15,000 to 40,000 madrasas, with a student body of almost 2 million (according to the BBC), are incubators of radicalism where young, impressionable boys from poor homes are sent ostensibly to receive free education and food but in fact to be instructed in hardline Wahhabism (a strict version of Sunni Islam practised in Saudi Arabia) as per the instructions of their financiers and organisers, the Saudis. By the time they “graduate”, they are fully fledged jihadists and recruited as foot soldiers by banned terrorist organisations such as Lashkar-e-Taiba, which orchestrated the Mumbai attacks in 2008, or Lashkar-e-Jhangvi, which targeted Sri Lankan cricketers in Lahore in 2009, or indeed Tehreek-e-Taliban, which attacked a school in Peshawar in 2014, murdering 132 schoolchildren.

This infrastructure of jihad, conceived, organised and financed by Saudis, has been exported all over the Muslim world to systematically destroy plural, liberal traditions of Islam and replace them with Wahhabism. In the Philippines, it has spawned Abu Sayyaf, designated a terrorist organisation by the UN and UK, among others. In postwar Kosovo, Saudi Arabia and other Gulf states have financed the construction of hundreds of mosques, Qur’an schools and visits by preachers to gradually undermine the tolerant, liberal Islam bequeathed by the Ottomans. In the Saudi-sponsored madrasas of Afghanistan, Islamic extremists from Malaysia, Thailand, Chechnya and central Asia have received instruction in hardline Islam.

Wahhabism made inroads into Pakistan in the early 80s, when I was a schoolgirl in Lahore. I remember when it became mandatory for female newscasters to cover their heads. Mullahs began appearing on television insisting women should confine themselves to their homes. Dance was banned. Cinemas closed down. Someone scrawled a sign on a wall near my house declaring Shias (a minority Muslim sect) to be kafirs (unbelievers). Now the signs go further: they incite believers to kill Shias. And indeed, over the past 20 years, thousands have been killed. Two of my cousins, prominent Shia men in their districts, were gunned down in broad daylight by a Saudi-backed Sunni terrorist organisation called Sipah-e-Sahaba. Ahmedis (another minority deemed apostates by Wahhabis) and Christians have fared even worse. They have frequently been massacred in their places of worship; those who could afford to do so have left the country. Ancient Sufi shrines, the last strongholds of a liberal Islam, have been bombed up and down the country. In February, a grenade and suicide bomb at a shrine in Sehwan, Sindh, killed at least 88 people and injured more than 250. Anyone who resists or criticises – activists, journalists, religious leaders, lawyers, politicians, artists – has been silenced.

So yes, Theresa May, let’s, by all means, have a “difficult conversation” with Muslims. I entirely agree: “enough is enough” and there has been “far too much tolerance of extremism”. I loathe the killers as much as you, but please let’s not confine ourselves only to the foot soldiers. When we converse, let’s be honest and even-handed for once. Let’s start by making public the findings of the report commissioned by your Conservative predecessor, David Cameron, into the funding of jihadi groups in the UK. Instead of regulating cyberspace, why not regulate the flow of funds from Saudi Arabia into the UK? Until you are prepared to do that, Mrs May, let’s not waste our breath on meaningless conversations.